Actuating mechanism for auxiliary doors



April 6, 1937. v -A. M. GRAFF 2,075,937

ACTUATING MECHANISM FOR AUXILIARY DOORS Filed Feb. '7, 1956 2 Sheets-Sheet l 25 v 21 r--- 14 J! i i a 54 ii' I 8 H i u L- m Ennentof Gum m. 1

Gttornegs April 6, 1937. M GRAFF 2,075,937

ACTUATING MECHANISM FOR AUXILIARY DOORS Filed Feb. 7, 1956 2 Sheets-Sheet 2 ISnventor 5; B r a $945 (Ittomegs Patented Apr. 6, 1937 UNITED STATES ACTUATING MECHANISM FOR AUXILIARY DOORS Amos M. Grafi, York, Pa., assignor to York Ice Machinery Corporation, York, Pa., a corporation of Delaware Application February 7, 1936, Serial No. 62,869

Claims.

This invention relates to door actuating means, and particularly to actuating means for auxiliary doors.

The principal contemplated field of use for 5 the device is in connection with meat storage rooms in which it is customary to make use of a metal track on which trolleys carrying the carcasses run. In such case the main doorway is closed by a heavy insulated door which must 1() clear the track and consequently the track is accommodated by a smaller doorway which is in effect an upward extension of the main doorway. The auxiliary doorway must be closed by an auxiliary door when the main door is closed, as otherwise the entrance of warm air from outside the refrigerated space would increase the refrigerative load and cause rapid frosting of the cooling coils in the refrigerated space.

Many devices have heretofore been proposed but none has proved entirely satisfactory. One difficulty encountered with prior art devices is that many of them seek to actuate the auxiliary door positively in both directions from the main door. The main door is heavy, and in some in- 25 stances is cammed open by actuation of the latch. At any rate such doors are customarily operated with considerable force in both directions and if the auxiliary door sticks, and particularly if it freezes shut, as sometimes occurs, the actuating mechanism is subjected to severe stresses.

One of the prime purposes of the present invention is to produce an extremely simple actuating mechanism in which the opening move- 35 ment of the main door is permissive as to the opening movement of the auxiliary door and its actuating mechanism, so that if the auxiliary door sticks closed the actuating mechanism will not be overloaded. 7

Another object of the invention is to secure gravity actuation of the auxiliary door in an opening direction, thus avoiding the use of springs which have proved objectionable in this service.

Another feature of the invention is the interposition of a buffer between the main door and the actuating mechanism for the auxiliary door, this buffer mechanism serving during the closing operation, to relieve the shock between the 50 main door and the weight which urges the auxiliary door in an opening direction. This cushioning mechanism is an important feature because the masses involved are substantial and the cushioning mechanism thus eliminates de- 55 'structive shocks.

Another feature of the invention is the arrangement of what might be described as a parallel motion linkage between the actuating weight and the auxiliary door, the parallel motion linkage being so contrived that the buffer has translatory motion in a curved path and thus operates in direct thrust with the main 'door throughout its range of operative engagement therewith.

A preferred embodiment of the invention will now be described in connection with the accompanying drawings, in which,-

: Fig. 1 is a vertical section taken on the plane of the track and showing the upper portion of the main doorway and door and the auxiliary doorway and door. Both doors and the auxiliary door actuating mechanism are shown. in full lines in their closed position. A second position is indicated in dotted lines in which the auxiliary door and its actuating mechanism are in open position with the main door just engaging the buffer at the commencement of coactive relation in a closing direction.

Fig. 2 is a front elevation of the structure shown in Fig. 1, the parts being shown in the position indicated in dotted lines in Fig. 1.

Figs. 3, 4 and 5 are diagrams illustrating'three instantaneous positions of the auxiliary door and its actuating mechanism, Fig. 3 being closed position, Fig. 4 being intermediate position and Fig. 5 being open position.

Referring first to Figs. 1 and 2, 6 represents a portionof the doorway. i represents the marginal frame of the door. 8 is the front sheathing of the door and 9 is the rear sheathing of the door. The space H within the marginal frame 1 and between the front sheathing 8 and rear sheathing 9 is customarily filled with cork insulation. The rear sheathing 9 does not extend beyond the marginal frame I and seals against a rabbet I2 by means of a gasket [3. The front sheathing 8 projects beyond the marginal frame I and carries a gasket M which seals around the margin of the doorway. This construction is common in the art. The hinges for the main door are not shown but customarily are placed on one vertical edge so that the door swings on a vertical axis. The manner of hinging the main door is not, however, a feature of the invention, as the device can be adapted to doors varying in the specific form of hinging used.

The auxiliary doorway is indicated at l5 and forms an upward extension of the main doorway serving to accommodate the track IS on which the trolleys, not shown, run. The auxiliary door I1 is mounted to swing on a horizontal axis by means of trunnions !8 which turn in gudgeons IS. The auxiliary door has a notch 2| which accommodates the track l6 when the door is closed, with the result that except for a slight clearance around the track IS, a tight closure is efiected. The auxiliary door ll seals by means of a gasket 22 which extends along its upper and two side margins but need not extend along the lower margin and does not extend across the slot 2|. The seal at the lower edge of the auxiliary door is produced by a flexible sealing strip 23 which engages the upper edge of the front sheathing 8 of the main door. Bolted to one side of the doorway I5 is a plate 24 which carries a trunnion 25 on which an actuating weight 26 for the auxiliary door is journaled. The weight is removably retained on the trunnion by a nut 21 with the usual washers. The weight 26 is formed with a bifurcated downward extension, between the arms of which an offset link 28, whose form is clearly shown in Fig. 1, is received. A pivot pin 29 hinges the link to the bifurcated extension. The upper end of the link 28 is pinned at 3| to a hinge bracket 32 mounted on the auxiliary door H, the bracket being attached to the door by any suitable means, screws being indicated.

The link 28 has a downward extension beyond the pivot 29 in which a plunger 33 is slidably mounted, the plunger being slidable in a direction normal to the plane of the main doorway. The plunger 33 preferably takes the form of a bolt whose nut 34 serves as a stop to limit its forward motion. A coil compression spring 35 urges the plunger 33 forward relatively to the link 28 so that the bolt and spring serve as a spring buffer. The head of the bolt engages a strike plate 36 mounted on the inner sheathing 9 of the door.

The following dimensional relationships, indicated on Fig. 4, are important. The radial distance A from the trunnion 25 to the pivot pin 29 is equal or substantially equal to the radial distance B from the axis of gudgeon l8 to the axis of pivot pin 3|. The distance C from the axis of trunnion 25 to the axis of gudgeon I8 is equal or approximately equal to the distance D between the pivots 29 and 3|. From this it follows that the link 28 has translatory motion in a curved path as has the plunger 33 which it carries. Consequently the axis of the plunger 33 is normal to the plane of the main doorway in all positions of the auxiliary door. The center of gravity of weight 26 is so related to the trunnion 25 on which the weight is mounted, that the weight urges the auxiliary door in an opening direction and the bifurcated extension of the weight 26 is provided with a stop 3'! which collides with the extension of link 29 and limits the opening movement of the auxiliary door.

The operation of the device requires only a very brief description.

With the doors in closed position, as indicated in full lines in Fig. 1, the spring 35 is slightly compressed so that the link 28 is forced rearwardly and the door I! is drawn tightly closed by a toggle action developed between the link '28 and the downward extension of the weight '26. As the main door opens the plunger 33 follows the door to the limit of the plungers motion, after which the opening movement of the auxiliary door I! beyond the reach of the weight 26 may commence. If the opening movement of the main door is rapid the opening of the auxiliary door may lag somewhat as a result of the inertia of the weight 26, but in any event the weight opens the auxiliary door so that if this be stuck or frozen shut the actuating mechanism will not be overstressed. The auxiliary door then swings from the position of Fig. 3 through the position of Fig. 4 to the position of Fig. 5 in which the auxiliary door is fully open.

Assuming that the main door is moved to its fully opened position and thereafter closed, the auxiliary door Will remain open until the main door is nearly closed, that is, until it reaches the dotted line position of Fig. 1. In this position it engages the head of the plunger 33 and because of the inertia of the Weight 26 will compress the spring 35 to a greater or less extent, depending on the speed of closing movement of the main door and the inertia of the weight 26. In any case the buffer spring will permit sufficient lag in response of the weight 26 to the impact of the closing door to relieve the mechanism of destructive shocks. It also develops a closing stress on the auxiliary door when the main door is closed. The final closure of the auxiliary door is usually slightly later than the complete closure of the main door.

The device is simple and rugged in construction and easy to mount in place. Its working parts are all accessible for inspection or repair when the main door is open. It provides a substantial yielding closing force on the auxiliary door when the main door is closed, and affords adequate protection to all the working parts against the severe shocks which are sometimes generated by rapid opening and closing of the main door.

What is claimed is,

1. The combination of means forming a main doorway and an auxiliary doorway; a main door and an auxiliary door for closing respective doorways; hinge means supporting the auxiliary door; a linkage associated with the auxiliary door, comprising a pivoted weight and a connecting link, the linkage having a toggle action when the auxiliary door is closed and the weight biasing the linkage in a door opening direction; and a yielding buffer carried by the connecting link in the path of the main door.

2. The combination of means forming a main doorway and an auxiliary doorway; a main door and an auxiliary door for closing respective doorways; hinge means supporting the auxiliary door; a linkage associated with the auxiliary door and arranged to have a toggle action when the auxiliary door is closed; yielding means biasing said linkage in a door opening direction; and yielding means for establishing a driving connection from the main to the auxiliary door as the main door approaches closed position, the last-named means being stressed when the main door is fully closed.

3. The combination of means forming a main doorway and an auxiliary doorway; a main door and an auxiliary door for closing respective doorways; hinge means supporting the auxiliary door; a linkage comprising a member hinged to swing on an axis parallel with the axis of said hinge means and a link hingedly connected with said member and door at such points that the link has substantially translatory motion; means biasing said linkage in a door-opening direction; and means carried by said link and adapted to be engaged by the main door to close the auxiliary door as the main door approaches closed position.

4. The combination of means forming a main doorway and an auxiliary doorway; a main door and an auxiliary door for closing respective doorways; hinge means supporting the auxiliary door; a linkage comprising a member hinged to swing on an axis parallel with the axis of said hinge means and a link hingedly connected with said member and door at such points that the link has substantially translatory motion; means biasing said linkage in a door-opening direction; and

yielding means arranged tov react between said main door and link as the main door approaches and after both doors reach closed position.

5. The combination defined in claim 4 in which the yielding means comprises a spring urged plunger guided in said link to shift in a direction substantially normal to the plane of the main doorway.

AMOS M. GRAFF. 

